Compressor



J. H. DENNEDY.

COMPRESSOR. APPLICATION FILED AUG.28, 1920.

Patented Ma 23, 11822 UNHT M,- s career castes.

JAMES H.

comrnnsson.

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Specification of Letters Patent. Pmbentgdl lwajy 23 1922,

Application filed August 28, 1920. Serial No. 406,595.

exact description, reference being had to the accompanying drawings.

This invention relates to compressors for gaseous substances and especially to such compressors as are used in connection with domestic refrigerating systems although not limited to such use. The objects of the invention are the provision of a device of great simplicity, of quiet operation, and of low cost of running; the provision of a device of this characterwhose moving parts shall be very light, of small clearance, and not liable to get out of repair; While further objects and advantages will become apparent as the description proceeds. i

In the drawing accompanying and forms inga part of this application, I have shown oneof the many mechanical structures in which my inventive idea can be embodied, it being understood that these drawings are designed to illustrate only the general idea of my invention and not to limit me to the particular structures therein shown. In these drawings Fig. 1 is a vertical sectional View through a simple two-cylinder compressor embodying my improvements; Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. 1; and Fig. 3 is a separated perspective view ofone of the pistons with its valves.

Describing the parts by reference characters, 1 represents the outer casing of the compressor which is formed with a crank case 2; 3-3 represent cylinder sleeves located in such casing and held in place by the topplate 4rabove which is secured the hollow cap 5. Reciprocably mounted in the sleeves are the pistons 8-8 whose travel is from a point closely adjacent the plate 4 to a point just beyond the side ports 9-9 with which the sleeves. are formed. These side ports communicate both with the inlet pipe 10 and with a passageway; 11 that leads to the crank case 2. i

Formed upon the head of each piston 8 is a shallow, transverse, flat-bottomed slot 12 intersected by a screw hole 13 and also by one or more ports 1 1. For reasons of symmetry and of manufacturing convenience I prefer to have the screw hole 13 at the center and to employ two ports 1414 one at each side and as near the piston wallas convenient; also the head of the piston is preferably thickened inside the screw hole so as to form a closed boss 15. However within the scope of'my invention other arrangements can be Employed, as for example a screw at one end 'fid a port at the other.

- Located in this slot 12 is a flap valve, preferably consisting of a sheet or sheets of thin spring metal held in place bythese screws. In the present embodiment this valve consists of two sheets or strips 17 18, the upper being of spring steel and the lower of phosphor bronze; although I do not limit myself either to a multiple sheet or to the use of these metals. I have shown a screw of the fillister head type projecting considerably above the head of the piston since this is easier to manufacture and has less adverse affect upon the sp'ringiness of the valve sheets than would be the case if the head of the piston were counter-sunk and the sheets stamped to conform thereto. The plate 4 is formed with outlet ports 2020 one for each cylinder and arranged so asto permit the head of the screw 16 to enter freely therein when the piston is at the top of its stroke. This not only enables the piston head to-be brought very close to the end of the cylinder, but even expels the gas which would otherwise remain pocketed in this opening, which at high pressures, and with a small cylinder bears a noticeable proportion to the piston displacement. I have shown the ports 20-2O as closed by automatic valves 21-21, governed b the spring 22, but the particular kindof valve here used is wholly independent of the present invention.

Upon each down stroke of each piston the tendency is to pull a vacuum in the upper part of the cylinder until the port 9 is uncovered, but the production of a vacuum is prevented'by the raising of the valveplates DENNEDY, OF DETROIT, 'MICH IG-AN', ASSIGNOR TO KELVINATOR CORPORA- ,t TION, OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE.

and the entry of gas from the crank case as shown by the arrows aa, in Fig. 1, such gas having entered the crank case through the pipe 10 and passagewa 11. As soon as the in piston heads I find less trouble in maintaining tight seating with the Valves here shown. I am enabled to make the piston lighter, its action is less noisy and the clearance is decreased. Also the present con- 4 structlon is more practical for small sized pistons.

Having thus described my invention, What I claim is:

1. In a compressor, a piston having on its head a Wide, shallow, flat bottomed slot, the

bottom of said slot having a port and a flap valve of fiat elastic, sheet metal located in said slot.

2. In a compressor, a cylinder having at one end an apertured closure, an automatic valve for said aperture and located on the outside of said closure, a piston in said cylinder, and having an inlet port in its head, a valve for said port, and a valve securing member carried by said piston and projecting beyond the head of the same and adapted to project into said aperture when said piston nears said closure.

In testimony whereof, I hereunto afiix my signature.

JAMES H. DENNEDY. 

